Circuit breaker



May 22, 1951 o. vo-N MEHREN 2,554,281

CIRCUIT BREAKER Filed July 9, 1946 @ww we@ Patented May 22, 1951 CIRCUIT BREAKER Oswald von Mehren, Lorain, Ohio, assigner to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 9, 1946, Serial No. 682,195

This invention relates to circuit breakers and more particularly, to circuit breakers of the type that are tripped instantaneously on overload currents above predetermined values and after a time delay on lesser overload currents.

One object of the invention is to provide a circuit breaker with an improved electromagnetic trip device having a tripping armature and a time delay means `which has no mechanical connection to the tripping armature.

Another object of the invention is to provide a circuit breaker with an improved electromagnetic trip device having a movable tripping armature and a hermetically sealed time delay device magnetically connected to the armature for delaying tripping operation of the armature.

Another object of the invention is to provide a circuit breakerwith an improved electromag netic trip device having a movable tripping armature and a time delay device disposed in a hermetically sealed casing for delaying tripping operation of the armature, said armature being disposed externally of said hermetically sealed casing.

Another object of the invention is to provide a a circuit breaker having an improved electromagnet-ic trip device according to the preceding paragraphs With means for preventing false operation of the trip device in response to sudden shocks or jarring forces.

Another object of the invention is to provide a circuit breaker with an improved trip device, time delay means and shock proof device according to the preceding paragraphs all of said devices being readily removable as a unit without disconnecting the moving parts.

The novel features that are considered characteristic of the invention are set forth in the appended claims. The invention itself, however, both as to structure and operation, together with additional objectsI and advantages thereof will be best understood from the following detailed description of one embodiment thereof when read in conjunction with the accompanying drawing, in which:

Figure l is a side elevational View, partly in section, of a circuit breaker embodying the invention, and

Fig. 2 is a iront elevational view of the trip device Iwith the scale plate partly broken away for clearness.

Referring to Figure l of the drawing, the refern ence numeral I designates a base of strong insulating material which supports the various parts of the circuit breaker. A pair of terminals I3 14 Claims. (Cl. ZOO-108) and I5 are suitably secured to the base and. each terminal has one or more connecting studs i9 which extend through the back of the base and serve to electrically connect the breaker to the circuit which it controls.

The upper terminal I3 has a Contact block 2i oi rigid conducting material secured thereto; and

a rigid contact block 23 secured to the base is electrically connected to the lower terminal l5 through the energizing winding of the trip device of the breaker, which will be hereinafter described.

The contact means and mechanism of the cir cuit breaker illustrated are similar to the circuit breaker fully disclosed in Patent No. 2,214,471 issued September l0, 1940 to Leon R. Ludwig and Merle E. Horn, and assigned to the assignee of the present invention. Hence only a brief description of these parts Will be given in this application.

The main stationary ccntacts 25 and 2l are rigidly secured to the Contact blocks 2| .and 23, respectively; and the auxiliary stationary contacts 29 and 3| are secured to a triangularlyshaped contact platform 33 of conducting material which is mounted on the upper portion of the block 2| for limited tilting and rocking movement by means of pins 35 projecting from the opposite sides of the platform which engage in slots 3l provided in a pair of side walls 39 secured to the block 2|. The platform 33 is biased outwardly from the base I I by a plurality of springs Iii and 43, and outward movement oi the platform is limited by the engagement of the pins 35 Iwith the outer ends of the slots 31 and by stop projections carried by the platform adjacent its upper end. The platform 33 and, consequently, the auxiliary contacts 2Q and 3| are electrically connected to the terminal I3 by means of a flexible shunt conductor 4l.

The movable contact means of the circuit breaker comprises a channel-shaped contact arm ai! oi conducting material which is rigidly secured to a pivoted switch member 5I by means of a plurality of screws 53. The contact arm i9 carries a main contact bridging member 55 for bridging the main contacts 25 and 2l, and an auxiliary contact member 5l for engaging the stationary auxiliary contacts 29 and 3 l the auxiliary ccntact member 5l being secured to the upper end oi the channel-shaped contact arm i9 by a plurality of screws 59.

The main Contact bridging member 55 is formed of rigid conducting material, and is loosely mounted on the contact arm 'i9 for lim- 3 ited movement relative to the contact arm toward and away from the main contacts 25 and 21 by means of a pair of studs GI secured to the contact carrying arm 49, only one stud 5| being shown. A pair of coil springs (not shown) encircle the studs 8|, and are disposed between the contact carrying arm 49 and the bridging member 55 for biasing the bridging member toward the stationary main contacts 25 and 21 with a predetermined force. The ends of the bridging member 55 are beveled to lie parallel with the beveled edges of the contact blocks 2| and 23, and have a pair of contacts 51 secured thereto for engaging the main stationary contacts 25 and 21.

The auxiliary contact member 51 is formed of rigid conducting material, and has an intermediate contact 69 and an arcing contact 'il secured thereto for engaging the intermediate and arcing contacts 29 and 3| of the stationary contact means.

A flexible shunt conductor 13 electrically connects the auxiliary contact arm 49 to the main stationary contact block 23. The iiexible ccnductor 13 has its upper end secured to the contact arm 49 by the lower bolts 53. The lower end of the flexible shunt conductor 13 is secured to the lower contact block 23 by means of a bolt 11.

The switch member 5| has a yoke-shaped lower end which is pivotally mounted between the side walls of a main frame 19 by means of a pivot pin 8|. The switch member 5| is movable about its pivot axis to open and closed circuit positions to open and close the contact means of the breaker by means of an operating mechanism indicated generally at 83.

The operating mechanism 83 is supported by the main frame 19 and comprises an actuating lever 85 pivoted on a pin 81 carried by the frame, and is connected to the switch member 5| by a link `89. An operating member 9| is also pivoted on the pin 81 for movement about the same axis as the actuating lever 85. The actuating lever 85 is normally and releasably connected to the operating member 9| for movement thereby by means of a pair of latches 93 and 95, which are pivotally mounted on the lever 85 at 91 and 99, respectively. The latch 93 engages a roller IBI carried by the operating member 9|, and this latch is, in turn, held in latching position by the auxiliary latch 95. The operating member 9| is adapted to be releasably held in closed circuit position by means cf a main holding latch |93 pivoted at H9, which releasably engages the roller IGI. The auxiliary latch 95 is provided with a curved tailpiece IE5 by means of which it is released to cause release of the latch 93 and consequent tripping of the circuit breaker by the release of the actuating lever 85 from its connection with the operating member 9 I. When released the actuating member 85 moves in a counterclockwise direction about the pivot axis 81, causing opening of the movable contact means. During this movement, a cam surface |01 of the lever 85 engages the beveled nose of the main holding latch |03, moving the holding latch to released position to effect release of the operating member 9|. The switch member 5| and the actuating lever 85 are biased to open position by means of a pair of accelerating springs |99 (only one being shown), which are connected at their upper ends to the switch member 5| and at their lower ends to the sides of the main -frame 19.

To close the circuit breaker after it has been tripped open, the operating member SI is rst moved in a counterclockwise direction about the pivot axis 81 to the open position to effect resetting of the latches and reestablishment of the releasable rigid connection between the actuating lever 85 and the operating member 9|. After the rigid connection is thus established, the operating member 9| is moved in a clockwise direction to closed position by means of a handle III to eiect closing of the contact means of the breaker. The clockwise or closing movement of the operating member 9| is limited by a portion 92 thereof striking a xed stop 94 on the frame 19. When the parts have been moved in closed position, the main holding latch |93 reengages the roller Il to hold the operating member in closed position. The stop 94 is located to permit a slight overtravel of the member 9| to insure proper engagement of the latch |03 with the roller l. It will be noted that the con struction of the operating mechanism is such that the movable contact means is trip-free of the operating member 9| that is, when the breaker is tripped, the contact means move to open position irrespective of theV position of the operating member 9|.

The mounting arrangement of the contact means is such that during opening of the breaker the main bridging member 55 is first separated from the stationary contacts 25 and 21, while the auxiliary contacts remain in engagement by reason of the outward movement of the contact platform 33 under the iniiuence of the biasing springs ti and 43. After the bridging member 55 has separated a predetermined distance from the main stationary contacts, the intermediate contacts 29 and 59 begin to separate'. This takes place as soon as the pins 35 engage the ends of the slots 31. During this time, the arcing contacts 3| and 1I remain in engagement due to the rocking movement of the contact platform 33. After the intermediate contacts have separated a predetermined distance, the arcing contacts 3l and 1| begin to separate. During closing, the contacts engage in the reverse order, as will readily be understood. it will thus be seen that the arc formed during separation of the contacts is drawn only between the arcing contacts 3| and 1|.

The circuit breaker is adapted to be tripped open either manually, or automatically, in response to predetermined overload conditions in the circuit, by means of a trip device indicated generally at I I5.

The trip device comprises a trip lever I |1 which is pivotally mounted intermediate its ends on the frame 19 by means of a pivot pin IIS, and an electromagnetic trip means, indicated generally at I2I, which is operable in response to the predetermined overload conditions to move the trip lever |81 to tripping position to cause automatic opening of the circuit breaker.

One arm |23 of the trip lever |I1 is offset and extends inwardly toward the base Ii of the circuit breaker, and has its inner end disposed immediately above the trip means I2! to be engaged and moved by a plunger of the electromagnet to eiect automatic tripping of the breaker. The arm 23 of the trip lever is provided with a projection |25 which is adapted to engage the curved tailpiece |95 of the auxiliary latc 35 to move this latch to released position upon movement of the trip lever to tripping position. The other arm of the trip lever I|1 forms a handle |21 whereby the trip lever may be manually moved to tripping position to effect manual opening of the circuit breaker. A spring |29 connects the arm |23 of the trip lever ||1 to an extension of the main holding latch |93 so that the spring thus serves to bias the main holding latch to latching position and the trip lever to its normal inoperative position, as shown in Fig. l.

The electromagnet |2| comprises a U-shaped magnetic yoke member I3|, a movable armature |33 having a trip rod |35 thereon, an energizing winding |31 having one end connected to the contact block 23 and the other end connected to the terminal I5, a time delay device illustrated generally at |39, and a shockproof device indicated generally at |4l.

The ends of the U-shaped magnet yoke |3| are formed over adjacent the base and are secured thereto by screw bolts |43 and |45, the bolt |43 also serving to secure the lower end of the contact block 23 to the base. A magnetic pole piece |41 threadedly engages an opening in the upper leg of the magnet yoke |3| and is locked in position by a lock nut |49. The pole piece |41 is provided with a central opening through which the trip rod |35 extends.

The armature |33 comprises an instantaneous trip armature |5| to which the trip rod |35 is secured and a time delay trip armature |53. The instantaneous trip armature comprises a cylindrical member of magnetic material closed at the upper end by a cap |55 also of magnetic material which threadedly engages the trip rod |35 as well as the cylinder |5|. A washer |51 of nonmagnetic material is rigidly secured to the upper face of the cap |55 as by brazing. A member |59 of non-magnetic material is provided with a ange |6| which threadedly engages the reduced upper end of the time delay armature |53 and a spring |63 is compressed between the flange |6| and an inwardly extending flange |65 on the lower end of the instantaneous trip armature |5|. A washer |61 of non-magnetic material surrounds the armature |53 and is disposed be tween the bottom of the armature |5| and a shoulder on the armature |53 so that upward or tripping movement of the time delay armature |53 causes the instantaneous trip armature |5| and the trip rod |35 to move therewith, but permits tripping movement of the instantaneous tripping armature |5| and the trip rod |35 independently of the time delay armature |53v by compressing the spring |63.

The time delay device |39 comprises a pair o separable suction discs |69 and |1| of non-magnetic material disposed in a hermetically sealed casing comprising an upper portion |13 and a lower portion both of non-magnetic material. The lower end of the upper casing |13 is reduced in diameter and istelescoped into the lower portion |15. This joint is sealed by braz ing or soldering. The lower disc |59 is disposed in the casing below the shoulder formed by the reduced portion of the upper casing |13 which limits the axial movement of the lower disc. The lower suction disc |69 is supported on a spherical bearing 11 to provide for accurate alignment of the faces of the discs when the de vice is reset.

The upper disc |1'| is slidably disposed within the reduced lower portion of the upper casing |13 and has a very slight clearance so as to act as a piston. The upper disc |1| is biased downward into contact with the lower disc |69 by means of a conical coil spring |19. After the casing |13- |15 is hermetically sealed, it is lled to a predetermined level with cil or liquid silicone of a suitable viscosity through an opening (not shown) which opening is then also hermetically sealed. Thev engaging surfaces of the discs |69 and |1| are lapped smooth and flat so as to form an oil seal therebetween when the discs are pressed into engagement by the spring |19. The upper casing |13 has a reduced portion |8| which extends upwardly through an opening in the lower leg of the magnet yoke into the lower turns of the coil |31. The portion |8| of the casing is shaped downwardly as at |83 to form a cupped portion to receive the enlarged lower end of the armature |53.

A cup-shaped armature |85 of magnetic material is rigidly secured in a counter bore in the upper face of the upper suction disc |1|. The member |35 may be secured to the disc 1| by any suitable means such, for instance, as brazing. Extending vertically through the bottom of the member |85 and also through the disc |1| are openings or passages |81 which are normally closed by means of a check valve |89 in the form of a disc. Horizontally disposed passages through the side wall of the cup-shaped men? ber |85 are provided Vto complete the passage to permit displacement of iluid to complete the passages to permit displacement of uid from below the disc |1| during a resetting operation.

Extending between the bottom of the cupshaped depression |83 and the bottom of the lower casing |15 is a tube |93 through which the trip rod |35 extends. The tube |93 is secured to both casing portions |13-|15 so as to form a hermetic seal preferably by soldering or brazing. The trip rod extends below the dashpot and has an enlarged lower end in which is mounted a pin |95, the ends of which extend into openings in arms |91 of a U-shaped lever |99 one arm of which lever is disposed on each side of the trip rod. The lever |99 is pivoted on a pin 20|, the ends of which are supported in spaced angular brackets 293 (Fig. 2) mounted by means of screws 295 on the lower leg of the magnet yoke |3| It will be noted that the dashpot is mounted between the brackets 253 and the magnet yoke and is supported in the position shown by the brackets 203 and screws 295.

A spring 291 is provided to bias the lever |99 in a counterclcckwise direction thereby biasing the movable core structure against operation. The spring 291 has one end anchored to the yoke portion 299 of the lever |99 and the other end of the spring is anchored to an adjustable stud 2H movable vertically in a slot 2| 3 in a scale plate 2 I5 attached by means of screws 2|6 to the magnet yoke |3| and to the brackets 203. A thumb nut 2|1 threadedly engages the stud 2|| to clamp it in the adjusted position. A clamp member 2|9 which has formed over portions engaging the slot 2 I3 to hold it in vertical position is provided with a pointer 22| (Fig. 2) which cooperates with a scale indicated at 223 on the scale plate 2|5 to indicate the tripping point at which the device is adjusted.

By unloosening the thumb nut 2|1 and moving the stud 2| up or down the tension of the spring 201 may be varied thereby varying the minimum overload current required to trip the breaker.

Energization of the winding |31 creates a magnetic ilux path from the lower leg of the magnet yoke i3! to the dashpot armature |85, across a high density flux path to the lower end of the time delay tripping armature |53, to the ange |65 of the instantaneous tripping armature |5|, to the Cap |55, across the air gap to the pole piece |4,f1 and thence to the magnet yoke |3|` When the winding |31 is energized in response to a persistent overload currentv in the low range of overload currents of, for instance, up to 300% of normal rated value the magnetic force across the air gap H11-|55 attracts the instantaneous trip armature upwardly but, since this force is insufficient to compress the spring |63, the force is applied through the spring |63 to the time delay trip armature |53. It will be observed that the lower end of the time delay tripping armature |53 is concave and that the upper end of the cup shaped armature |85 is beveled and that the sharp edges of the armatures |53 and |85 lie in substantially a horizontal plane when these parts are in their normal position. These edges are shape to produce an extremely high magnetic flux density in the airgap |53-485, thus forming a magnetic coupling between the time delay tripping armature |53 and the armature |85 which is rigidly secured to the upper sucker disc |1|. Due to the high density flux across the air gap |53|85, the armature |53 is prevented from immediate upward movement but the magnetic force is applied through the dashpot armature |95 to the upper suction disc |1|. After a predetermined time delay, depending on the magnitude of the overload current, the oil seal between the suction discs |69 and |1| is broken, whereupon the entire movable core structure including the dash pot armature moves upwardly raising the trip rod |35 to trip the breaker. During the tripping movement, the cylindrical portion of the armature 285 moves into the annular space between the inner wall |83 and the outer wall |8I of the reduced portion of the upper casing |13 which extends into the winding.

After the seal between the suction discs |69- |1| is broken the upward movement of the upper disc |1| is further delayed due to the fact that oil must lbe forced between the periphery of the disc 1| and the inner wall oi the casing |13. This retarding action occurs up to the point when the disc |1| clears the reduced lower portion of the casing |13 at which time the space between the disc |1| and the casing |13 is increased and permits a free flow of oil and removes the restraint from the moving core structure which is then free to move rapidly upward to trip the breaker.

After the breaker contacts are opened and the winding |31 deenergized, the armatures |5| and |53 are restored to their unattracted position under the influence of gravity aided by the spring 201. The downward movement of the tripping armatures is completely independent of the position of the disc |1| and the dashpot armature |85. The disc |1| is restored by means of the spring |19. As the disc |1| moves downwardly, the pressure of the oil through the passages |81 raises the check valve |89 and permits free flow of oil through the passages |81 and |9| to the upper side of the disc |1| thus permitting quick resetting of the dashpot device and quickly reestablishes the seal between the suction discs.

v Upon the occurrence of an overload in the intermediate range of overload currents, for exe ample, between 360% and 1000% of normal rated current, the force is insufficient to compress the spring |63 but is large enough to cause the oil seal between the suction discs |89 and |1| to break with negligible time delay. The breaker is tripped open on overloads in the intermediate range after a relatively short time delay occasioned by the plunger action of the upper disc 1| in the restricted portion of the casing |13.

Upon the occurrence of an overload above 1000% of rated current, or a short circuit, the instantaneous tripping armature |5| is attracted upwardly with such force that it compresses the spring |63 and moves to trip the breaker independently of the time delay armature |53 and without breaking the oil seal between the suction discs ISB-Ill. When an overload above 1000% of normal current, or a short circuit occurs, the magnetic coupling between the armature |53 and the armature |85 attached to the suction disc |1| is increased to the point when the attraction cf the instantaneous armature |5| overcomes the spring |63 and moves the armature |5| and the trip rod |35 independently of the armatures |53 and |85 to instantaneously trip the breaker. This sudden action does not break the magnetic coupling of the high flux density air gap |53-|85 and does not break the oil seal between the discs |1| and |69. The armature |5| and the trip rod |35 are reset following an instantaneous tripping operation by the spring |63.

The limits of the intermediate range of overload currents (300% to 1000% of normal current) set forth are to be considered merely by way of example and these may be varied considerably to suit particular requirements. For instance, by the provision of stronger or weaker springs entirely diierent sets of Values may be established.

The trip device is susceptible to sudden shocks delivered thereto in vertical direction and provision is made to prevent false tripping in response to such shocks or jarring forces. The means for preventing operation of the trip device in response to shocks comprises a lever 225 pivotally mounted on a pin 221 supported between the brackets 203. The lever 225 comprises two spaced parallel levers- 226 which straddle the arms |91 of the U-shaped lever |99 and between them carry a mass 229 mounted on a pin 23|. The ends of a spring 233 coiled about the pin 221 extend across the plane of the lever 225 and also across the plane of the vertical portion of one of the brackets 203 thus biasing the lever 225 and the mass 229 to a central position wherein pin 235, one end of which projects outwardly from each leg |91 of the U-shaped lever |99 are free to enter openings 231 in the ends of the levers 226 upon clockwise or tripping movement of the lever |99.

Upon the occurrence of a shock delivered to the trip device in vertical direction, the unbalanced mass 229 will cause the lever 225 to move in either clockwise or counterclockwise direction depending upon the direction of the shock thus moving the right hand end of the lever into the path of clockwise movement of the pins 235 to block tripping movement of the lever |99 and of the trip rod |35.

Having described the invention in accordance with the patent statutes, it is to be understood that various changes and modications may be made in the structural details and combination of elements disclosed without departing from some of the essential features of the invention.

I claim as my invention:

l. In a circuit breaker comprising relatively movable contacts and operating means therefor, an electromagnet operable to cause automatic operation of said operating means including an energizing Winding, a sealed chamber mounted in xed relation to said electromagnet, a first armature disposed externally of said chamber and movable upon energization of said winding to cause tripping of said breaker, a time delay device operable under certain circuit conditions to delay tripping movement of said armature comprising a pair of separable suction discs dis'- .posed in said sealed chamber, and a second armature disposed in said sealed chamber and attached to one oi said suction discs for restraining tripping operation of said rst armaure.

2. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, a trip mechanism operable to cause automatic operation of said operating mechanism, a xedly mounted sealed chamber containing a body of fluid, an electromagnet comprising a movable core structure disposed externally of said chamber and movable upon energization of said electromagnet to actuat'e said trip mechanism, time delay means for delaying tripping movement of said movable core structure comprising a suction disc disposed in said sealed chamber for delaying operation of said movable core structure, and an armature attached to said suction disc and disposed in said sealed chamber cooperating with said movable core structure upon energization of said electromagnet to form a magnetic air gap for restraining said core structure against tripping movement.

3. In a circuit breaker comprising relatively movable contacts and operating means therefor, a trip device operable to cause automatic operation of said voperating means comprising an energizing winding, a sealed chamber mounted in iixed relation to said winding, a tripping armature disposed within said Winding but externally of said chamber and movable upon energization of said winding to effect tripping of said breaker, time delay means comprising x'ed and movable suction discs disposed within said sealed chamber, and a second armature attached to said movable suction disc disposed Within said sealed chamber and responsive to overload currents to magnetically couple said movable suction disc to said tripping armature to restrain tripping movement of said tripping armature.

4. In a circuit breaker comprising relatively movable contacts and operating means therefor, a trip device operable to cause automatic operation of said operating means comprising an energizing winding, a tripping armature disposed Within said Winding and operable to effect tripping of said breaker, a sealed chamber mounted in xed relation to said winding, time delay means comprising fixed and movable suction discs disposed Within said sealed chamber, a second armature disposed outside of said Winding but Within said sealed chamber responsive to energization of said Winding to magnetically couple said movable suction disc to said tripping armature to restrain tripping operation of said tripping armature, and a third armature operable at times independently of said tripping armature to instantaneously trip the breaker.

5. In a circuit breaker comprising relatively movable contacts and operating means therefor, an electromagnetic trip device operable to cause automatic operation of said operating means comprising an energizing winding, a, trip memacs'gsi 10 ber movable to effect tripping of said breaker, a rst armature for actuating said trip member, a hermetically sealed chamber, a second armature disposed externally of said sealed chamber and operable in response to overload currents below a predetermined value to actuate said trip member, time delay means comprising a dashpot disposed Within said sealed chamber for delaying tripping operation of said second armature, a third armature disposed in said sealed chamber responsive to energization of said winding by overload currents to magnetically couple said second armature to said dashpot, and said rst armature being operable in response to overload currents above said predetermined value to instantaneously actuate said trip member independently of said second armature.

6. In a circuit breaker comprising relatively movable contacts and operating mechanism, an electromagnetic trip device operable to cause automatic operation of said operating mechanism, a xedly mounted sealed chamber, said trip device comprising an energizing winding, a tripping armature disposed in said winding but externally of said chamber and movable upon energization of said winding to effect tripping of said breaker, time delay means for delaying tripping movement of said tripping armature comprising a dashpot disposed in said chamber for delaying operation of said tripping armature, and a second armature disposed Within said sealed chamber attached to said dashpot for magnetically relating said dashpot to said tripping armature.

7. In a circuit breaker comprising relatively movable contacts and operating means therefor, a trip device operable to cause automatic operation of said operating means comprising an electromagnet having an energizing Winding, a hermetically sealed dashpot mounted in fixed relation to said Winding and having a portion extending into said Winding, a movable core structure disposed Within said winding but externally of said sealed dashpot, said movable core structureV being operable upon energization of said Winding to trip said breaker, and a magnetic element disposed within said sealed dashpot and forming a magnetic connection between said movable core structure and said dashpot to restrain said movable core structure against tripping operation.

8. In a circuit breaker comprising relatively movable contacts and operating means therefor, a trip device operable to cause automatic operation of said operating means comprising an electrornagnet` having an energizing winding, a hermetically sealed chamber mounted in xed relation to said electromagnet and having a portion extending into said winding, iixed and movable suction members disposed in said sealed chamber, a movable armature having a portion nested Within said portion of said chamber but disposed externally of said chamber and operable upon 'energization of said winding to effect tripping of said breaker, and a magnetic. member attached to said movable suction member and disposed \'vitriin said sealed ychamber and forming a magnetic connection between said movable armature and said movable suction member for restraining said armature against tripping operation.

9. In a circuit breaker comprising relatively movable contacts and operating means therefor, a trip device operable to cause automatic operation of said operating means comprising an electromagnet having an energizing winding, a xed hermetically sealed chamber having a portion extending into said winding, xed and movable suction members disposed in said sealed chamber, a movable armature disposed externally of said chamber and operable upon energization of said winding to effect tripping of said breaker, and a magnetic member disposed within said sealed chamber attached to said movable suction member and forming a magnetic coupling between said movable armature and said movable suction member for delaying tripping operation of said armature, said magnetic member in said chamber forming the sole coupling between said movable suction member and said externally disposed armature.

10. In a circuit breaker comprising relatively movable contacts and operating means therefor, a trip device operable to cause automatic operation of said operating means comprising an electromagnet, an energizing winding, a xedly mounted sealed chamber, a trip rod extending axially through said winding and said sealed chamber, a rst armature disposed in said winding and secured to said trip rod and operable in response to certain circuit conditions to actuate said trip rod to trip the breaker; a second armature operable in response to certain other circuit conditions to operate said rst armature to trip the breaker, a dashpot disposed in said sealed chamber for at times delaying operation of said second armature, and a magnetic member disposed in said sealed chamber for magnetically relating said dashpot to said second armature.

11. In a circuit breaker comprising relatively movable contacts and operating means therefor, a trip device operable to cause automatic operation of said operating means comprising an electromagnet, an energizing winding, a xedly mounted sealed chamber, a trip rod extending axially through said winding and said sealed chamber, a rst armature secured to said trip rod and operable in response to certain circuit conditions to actuate said trip rod to trip the breaker, a second armature operable in response to certain other circuit conditions to operate said rst armature to trip the breaker, said first and said second armatures being disposed externally of said sealed chamber, a dashpot disposed in said sealed chamber for at times delaying operation of said second armature, and a magnetic member disposed in said sealed chamber for magnetically relating said dashpot to said second armature.

12. In a circuit breaker comprising relatively movable contacts and operating means therefor, a iixedly mounted sealed chamber, a trip device operable to cause automatic operation of said operating mechanism comprising an electromagnet having an energizing winding, a tripping armature disposed externally of said chamber and movable upon energization of said electromagnet to effect tripping of the breaker, time delay means comprising a fixed suction member in said sealed chamber, and a movable suction member in said sealed chamber magnetically related to said tripping armature and cooperating with said iixed suction member to form a seal for restraining said armature against tripping operation, said chamber having a portion cooperating with said movable suction member after said seal is broken to provide additional time delay.

13. In a circuit breaker comprising relatively movable contacts and operating means therefor', a xedly mounted sealed chamber containing a body of oil, a trip device operable to cause operation of said operating means comprising an electromagnet having a movable armature disposed externally of said chamber and operable upon energization of said electromagnet to effect tripping of said breaker, time delay means comprising a xed suction member disposed Within said chamber, a movable suction member magnetically related to said externally disposed armature and cooperating with said iixed suction member to form an oil seal to delay operation of said armature, said seal delaying tripping operation of said armature for a relatively long time delay, said chamber having a portion c0- operating with said movable suction member after said seal is broken to delay tripping operation of said armature for a relatively short time delay, and a member movable in response to shocks for blocking tripping operation of said armature in response to sudden shocks or jarring forces.

14. In a circuit breaker comprising relatively movable contacts and operating mechanism therefor, a trip member operable to cause automatic operation of said operating mechanism, a trip device including an electromagnet, a xedly mounted sealed chamber, a fixed magnetic member supporting said sealed chamber, a first armature disposed externally of said sealed chamber and movable upon energization of said electromagnet to actuate said trip member, time delay means for delaying operation of said armature comprising a dashpot disposed in said chamber, and a second armature disposed in said chamber and connected to said dashpot, said second armature cooperating with said iirst armature to form an air gap of high density flux forming a magnetic coupling between said armatures for restraining said rst armature against movement to thereby delay tripping movement of said rst armature.

OSWALD voN MEHREN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,289,656 Cheney Dec. 31, 1918 1,330,094 Simon Feb. l0, 1920 1,903,135 Rees Mar. 28, 1933 2,200,109 Wilckens May 7, 1940 2,308,660 Kouyoumjian Jan, 19, 1943 2,337,565 May Dec. 28, 1943 2,357,959 Kouyoumjian Sept. 12, 1944 

